Upvoting posts and comments is allowed by the system. Self-upvoting is a debated issue. Technically there's nothing wrong with it. I do upvote all my posts (15-20 cents worth), almost everyone does that, but I rarely upvote my comments (I think I did that twice so far when I thought my comment was important). That being said, there are people with lots of SP that often upvote their comments. About two weeks ago, one whale upvoted his two-lined comment to almost $600!!! That sparked some very heated exchange. Other people use bots to upvote their comments, which many consider it abusive.