As Wikipedia becomes more popular, more and more social networkers seem to be finding their way in. You can tell them by their editing habits, and often even by their userpages. Blocking someone simply for editing userspace too much, for example, is probably likely to be controversial. People may ask the valid question, "Where is the disruption?" This is probably not a battle worth fighting. So, while it's probably not practical to outright block them, there are things we can do to discourage the use of Wikipedia as a personal homepage provider and social networking site. The general idea is that we should all look for ways to make Wikipedia a less attractive environment for the social networkers.
How do we do this?
Perhaps the most important thing is do not help them misuse Wikipedia. This by itself may make the problem much smaller. If they want help doing something useful, by all means help them. But if they want their userpage decorated or their autograph page signed, do not get involved. We cannot complain that so many newbies get the wrong idea about Wikipedia as long as we're actively encouraging these wrong ideas. If you see someone using Wikipedia for a homepage and not doing anything useful, blank their page and ask them to please stop doing that. Again, it's probably best not to block them, but let's not make it easy and convenient to misuse Wikipedia either. Also, think twice before demanding that they get involved with article content. If someone is sufficiently clueless as to have mistaken Wikipedia for a social networking site, do we really want them messing with important things like articles? Rather than going to great lengths to mentor them, try keeping your interactions with social networkers to a minimum. If they find that Wikipedia does not give them the personal interaction and chatting that they desire, perhaps they'll wander off and find some place that does.
But shouldn't we try to teach and nurture newbies?
Absolutely we should! But our resources are limited. Which newbies should we spend time on? I think there's far greater value in spending time helping those who are already interested in editing an encyclopedia than those who are not. If someone is not, it's unlikely that some amount of mentoring will change this. Instead, focus your effort where it's more likely to produce a useful result. If you're picking the worst mentoring candidates you can find rather than good ones, examine your own motivations carefully. Do you really think you're helping, or are you looking for an ego boost by taking on a challenging pet Pygmalion?
One problem is, if clueful editors simply don't get involved in things like Wikipedia:Adoption or User:Sharkface217/Award Center, this will not make them go away. Instead, it'll mean they're simply populated only by clueless editors. This probably does more harm than good. So, while the best solution may be to get rid of these things entirely, this may not be practical. Keep an eye on them, and try to limit the harm they cause.