tedster - 7:30 am on Mar 18, 2012 (gmt 0)
We work with large scale social data analysis - and I can tell you that false profiles are not that hard to detect. For example: run sentiment analysis on Tweets. Spam profiles almost never show mixed sentiment - they are usually all positive. Other techniques are applicable to other social situations.
This kind of manipulation might fool the average user, but it's not that hard to filter with enough data crunching power.