dvd436 2 of your methods are very time wasting, dont do them , firstly the forum posting, whilst it is usefull to have a link from a relevant forum (dofollow link) anymore than one link gives you no extra gain in terms of seo juice. so really one post is same effect as 300 posts. the making of multiple websites and then linking them all up is not something you should do because first of all all your websites will start out as untrustworthy in the eyes of google due to the site age and they will have no pr. also google can detect that all sites belong to one webmaster and give you a penalty for attempting link them up in order to get link juice. your other ideas however were good you should concentrate on those check this out http://forums.seochat.com/link-popularity-43/link-building-101t-124545.html
NIce point forum and nofololw link? How to check the link which forum has follow and which one has no follow. thanks