It does not send random PMs. It sent friend requests, because there were users who added you as a friend, therefor Friends management system sent them a requests
its good you mentioned this cuz I was wondering the same..I found this strange behaviour after I installed this MOD...some members received some random friend's request when the friend didnt even send the request. This was very few only. Maybe 1 or 2 friend's request messages for some users and not all! I was able to confirm this cuz when I installed this MOD on my site, I did not show the link to any users and there is NO CHANCE that my users knew about the mainpage feature at all. But 1 minute later after I installed the MOD, I received 2 friends request from my users who were not even online at that time and they dont even know me. it was weird and I was not sure why and how it happened! Also, at that time I received a friend's request from a moderator and she confirmed that she did not add me as a friend at all!
honestly speaking, it really did not bother me too much..I think, this is good in some ways since it gets some users started on this new feature and the whole idea is building friends and social network. This happened only once during the first installation and ever since then this mod has been working flawlessly. just thought I will share my experience with this random PMs....no biggie but just wondering why...that all...
BTW I cant wait for the next version to be released!!