Matt Cutts explains that although not following "100 links" recommendation will not result in Google automatically considering the page to be spammy, it is a good idea to follow the guideline as it will provide a better user experience and ...
If you end up with hundreds of links on a page, Google might choose not to follow or to index all those links. At any rate, you’re dividing the PageRank of that page between hundreds of links, so each link is only going to pass along a minuscule amount of PageRank anyway.
So if you would like to follow the guideline, how to count links in web page?
IE8 Developer Tools generates a nice report with a numbered list of all the links in a page when you choose View > Link Report from the Developer Tools menu. Although earlier versions of IE Developer Tools/Toolbar had this Link Report feature, the links were not numbered.
Also see:
Google Browser Security Handbook
IE8 Developer Tools Tips & Tricks - #5: Find Link Paths