How many links on a single page?

I did some research for a client on how many links should be used per page or on a site-map because I only knew about Google saying not to use more then hundred links at once:

“Keep the links on a given page to a reasonable number (fewer than 100).”

There are a lot of opinions out there but most likely everybody I asked stated that sticking below this limit is highly recommended (…maybe because Google says so…?). I’m not really sure about this but a potential problem might be to run into crawler limits – because there (theoretically) could be a hard limit that drops links above a predefined limit.

Another problem that you’ll be facing is the more links you have on page the less valuable is a single link – at least for Google’s PageRank. This can of course be controlled by using the “nofollow” attribute for links that should not get any link juice – but this can also be dangerous because consistently using “nofollow”-links can end in getting these pages dropped out of the index completely.

I my opinion Google needs to communicate a “verbal” limit which is used to identify for example link farms or something similar and exceeding the number of links will not result in links getting dropped but might trigger some kind of a notification which then maybe results in a check by a Google employee / engineer. What happens then can’t be said…