What kinds of Mormon missionaries are there? I'm used to seeing young missionaries travel in pairs, talking to people and visiting them, but I don't typically think of them as serving their missions online (as evidenced here) or doing other types of activities.

What kinds of missionaries (or missionary services) are there in the LDS Church and what do they do?
I am currently an LDS missionary so lets see if I can answer your question.


Elders: Two young men typically from age 18 to 25. Some rare cases are older. They travel from door to door, and teach those who are willing to listen.
Sisters: Two young women from age 19 to 25 who also go door to door and teach.
Service missionaries: Usually people who aren't capable of serving as elders for a variety of reasons. They are given specific jobs to help out where they can with the temples and humanitarian services.
Senior couples: A man and a wife whose children are all moved out from home. They don't go door to door, but teach those who are willing to listen who are found by other means. Usually online requests, or requests by members to teach their friends.
Senior sisters: Single sisters that don't have a husband to be companions with. They serve together and do the same things as senior couples.
Internet missionaries: People who cannot typically serve full time missions for various reasons, so they work online. Usually on LDS.org where people can request to talk with missionaries online. Recently missionaries have begun working on facebook as well, and that is becoming part of regular missionary service as well.


I hope that answers your question. If I find any more types of missionaries I will add them on.