A new study from Harris Interactive confirms through numbers what many of us have been noticing anecdotally: social networking spam is on the rise, and most users are concerned about it.

In the study, which was commissioned by Cloudmark (an anti-spam software company), 66 percent of the 972 social networking users polled indicated that they would be at least “somewhat likely” to switch to another social network if they “received a significant number unwanted, or spam, friend invitations, messages, or postings.”

Among the other findings from the study:

* 37% say they have noticed an increase in social network spam in the past 6 months

* 63.9 was the average number of unwanted messages received by social networking users in the past year.

* 80% of users indicated that they are “at least somewhat concerned” about the issue

Of course, the definition of spam is fairly broad here – by including friend invites and presumably application invites, it’s hard to think that any social network users would not have been hit by at least some form of spam recently.

However,