I've visited all my 460 neighbours last night, and deleted those who don't seem active anymore. I still have a suprisingly high nummer of 260 neighbours left. I'm sorry, I couldn't bring myself to posting politie messages on 200 walls, mostly of people who won't ever read them.
I posted a msg on my own wall, starting that if I wrongfully deleted you, you can always reinvite me.
The clogging-info is just an urban legend that doesn't seem to be forgotten. The systeem isn't clogged when you send out requests to 260 neighbours. It's just that only the 20 first responders get to see your request that day. The next day, also 20 first responders get to see your request, etc. Etc.