At some point in your work you're going to have questions. If you don't see what you're looking for in R search, ask a question in one of the R forums listed below. These are all sites that are active with people that use R. You can learn quite a bit by surfing these forums and reading the questions & answers of others.
When posting to the forums you can save yourself from being flamed by following a few simple rules. If you need help with code, post the code and the output. Also, given the geeky topic, this is not the place for open ended "which do you like best..." type posts. Stay on topic.
Nabble - This site has a funny name, but unlike other forums on this page it is specific to R. The user base is knowledgable & helpful. Questions here range from R & programming to statistical methods & data mining. As long as your question is specific, it should be answered quickly.
Stack Overflow - This is a popular forum focused on programming, with a tag for questions related to R. The community here is active & helpful. Keep in mind that this is a place for programming questions. If you have questions about the underlying math or methods, this isn't the place.
Cross Validated - A sister site to Stack Overflow, this forum deals with statistics & statistical programming. Any questions about programming R, statistical methods, data mining, big data, etc, are welcome here.
R-Help Mailing List - Before forums, there were mailing lists. This mailing list has been active since the late 90's and is still very active. You can post a question if you subscribe to the list. The archive is searchable & has a ton of great info.