I don't care what all the ignorant, prepubescent kids say. Runescape is a great free, mmorpg with decent graphics and quality entertainment.
The only negative aspect of Runescape I can think of is all of the arrogant children who "pwn" and find ways around typing out their full words.
I used to love this game when I was younger, and played it on and off. I took a lot of breaks, knowing I was becoming addicted. I'm considering starting again, after coming back to discover the enhanced graphics and many other improved aspects that were added while I was away. The membership fee is optional, so there's nothing wrong with Runescape coming to Kongregate.
Speaking of that, for those that claim it will only attract children that use improper grammar, and beg for "fr33 gp an addy," try to use some common sense. Why would they visit Kongregate instead of the actual website? All this can do is attract more mature people from Kongregate TO Runescape.