Visual Studio 2015 / 2013 Users: Please use Supercharger instead. It includes a much enhanced version of this tool plus a lot more, all based on a high performance, multithreaded parsing engine with almost zero UI thread overhead. 

Supercharger can be found/downloaded from the Visual Studio Gallery:
/vsgallery/f58941e3-13c6-4e97-9235-195f6f380ea3

Supercharger screenshots and details:
https://supercharger.tools

Thank you!

Overview

VS10x Comments Extender is a Visual Studio 2013/2012/2010 extension built with the goal ofmaking code commenting more useful from both a documenting and a productivity standpoint. By using a simple comment prefix system, you can change the default formatting of a comment by affecting its foreground color, font size and style. It works with C#, VB, C++, F# and markup language (HTML, ASPX, XML, XAML) documents.

Details

Let's start with a brief example of what VS10x Comments Extender can help you achieve:

How does it work? Well, when you start a comment with // (C#, C++, F#) or ' (VB), you can add some extra characters (minimum one, maximum three) in order to define how this comment will look like.VS10x Comments Extender will interpret these prefixes and format the comment accordingly. Here are the possible combinations:

Also, you can format task comments (TODO, HACK, UNDONE) in terms of foreground color.

Let's have a look at two comment styles (i.e. "removed code" and "important") - notice thestrikethrough font style and grayed-out color used to visually isolate removed code, and thered color used to emphasize an important comment:

Additionally, a "question" style is available (actually, you can use any different meaning according to your needs) that stands out by using amagenta foreground color:

And this obviously is not all of it. You can affect the size - currently,two large sizes (large and extra large) are implemented; see the below "Column" comment text in extra large size:

Customization

VS10x Comments Extender can be customized in terms of colors, font size and enabled/disabled state for each comment style.

Color customization can be performed in the Visual Studio "Fonts and Colors" options page (look for items starting with "Comment, "):

Font size for large and extra large styles, as well as enabled/disabled state can be set by opening the "VS10x Comments Extender - Customize" dialog box from the VS10x menu entry on the main menubar.

What's new

• 1.44 - Dec 08, 2014
  • Fixed a problem related to dark theme detection
• 1.43 - Oct 23, 2014
  • Multiple 'VS10X' menu items were sometimes added to the main menu bar.
• 1.42 - Jul 31, 2014
  • Fixed an issue in the services definitions package
• 1.41 - Jul 27, 2014
  • Fixed an exception condition
• 1.40 - Jul 09, 2014
  • Necessary update due to a VS10x Extensions common lib change
• 1.39 - Jul 02, 2014
  • Preliminary support for Visual Studio 14 (CTP).
• 1.38 - Jun 26, 2014
  • Relocated some common VS10x extensions code to a common lib. Sync release with other VS10x extensions. Update highly recommended.
• 1.37 - Nov 20, 2013
  • New identity icon.
• 1.36
  • Sync release with CodeSMART 10.17
• 1.35
  • Added VS 2013 support.
• 1.34
  • Sync release with the rest of the VS10x Extensions due to a common library being changed.
• 1.33
  • Setting changes in "VS10x Comments Extender - Customize" take effect immediately (i.e. there's no need to reopen code windows or restart VS anymore).
• 1.32
  • Fixed crash conditions on Visual Studio 2012.
• 1.31
  • Fixed a versioning issue, especially important to users having the full CodeSMART suite or other VS10x extensions installed.
• 1.30
  • Fixed incompatibility issues with VS11 Beta.
• 1.27
  • Preliminary support for VS11 (VS 2012?).
• 1.26
  • Fixed UI elements scaling issues (when custom DPI settings were used) in the "Customize" dialog.
• 1.25
  • The comment ending tag is now excluded from formatting in markup languages (HTML/ASPX/XAML/XML).
• 1.24
  • Added support for markup language documents, i.e. XAML, XML and HTML (ASPX included). Only for single-line comments, or the first comment line in case of multi-line comments.
• 1.23
  • Rebuild caused by a change in a VS10x common DLL.
• 1.22
  • Rebuild caused by a change in a VS10x common DLL.
• 1.21
  • Rebuild caused by a change in a VS10x common DLL.
• 1.20
  • Extended the trial time with 5 more days since the earliest expiration date would have been on a Saturday.
• ...
• 1.17
  • Added an option to control whether or not a whitespace is reqired after the marker.
    In other words, if the option is 'on', and the entered text is
        //xComment
    then the 'Comment' text will not be colored. However, if the entered text is
        //x Comment
    then the 'Comment' text will be colored.
  • Redesigned the 'Options' dialog box.
• 1.16
  • Added options to control the availability of the small and extra small size comments (//-, //-- in C#/C++ and '-, '-- in VB).
• 1.15
  • Reset the expiration system
• ...
• 1.11, 1.12
  • Attempts to solve a crash.
• 1.10
  • Beta expiration system update.
• 1.9
  • Added in-string testing; the algorithm is not comprehensive, as a I preferred to favor speed over comprehensiveness (i.e. it will work in 99% of the cases, as making it work in 100% of the cases would have tripled processing time).
• 1.8
  • Fixed some exception conditions.
• 1.7
  • FIX: Beta expiration message was locking the UI thread.
• 1.6
  • FIX: User-defined large / extra large comment sizes were not saved/restored.
  • NEW: User-defined large / extra large comment sizes are now expressed relatively (i.e. by percentage) to the code window font size.
• 1.5
  • Significant speed optimizations
  • Added support for task comments (i.e. TODO, HACK, UNDONE)
  • Redesigned the Options dialog so that it can accomodate the new features
  • Changed name to "VS10x Comments Extender" (i.e. plural) for better web/gallery search matching.
• 1.4
  • Sync release with CodeSMART 10.3
• 1.3
  • Corrected a typo in the Options dialog.
• 1.2
  • Besides C# and VB, "VS10x Comment Extender" now supports C++ and F# as well.
• 1.1
  • The behavior can be fully customized now (comment styles enabled/disabled state, font sizes for large/xlarge). Colors can still be changed in the VS "Fonts and Colors" dialog.
  • VS10x Comment Extender participates now to the VS10x entry on the main menu bar. For now, "VS10x Comments Extender - Customize" is the only option it adds.
• 1.0
  • Initial release.