There are a number of different tools which can be used for reflection; I’ve been using this blog as a way of keeping track of what I think about things, but there are other ways of doing this eg using wikis and eportfolios, as well as blogs.
I guess by using a blog you can easily see what’s most recent and how the writer’s views have changed over a period of time. They’re also fairly easy to set up and can be used by anyone.
A wiki makes it easier to see the links between different sections and have a set start page to view the site from. I think they’re not as good for showing development over time as they are easily editable and you can’t always tell when a particular bit on a page was written, at least not easily.
Eportfolio systems are the easiest when trying to collate information that is in a range of formats, which you can then comment on and then organise in whatever way you want to. They also have structured forms that can help those unused to reflecting as they give you a framework to start from. Eportfolios are a growing tool within the academic sector as they’re perceived as a way of helping students to reflect and allow them to collate evidence of what they’ve done to aid assessment and employment. However their use beyond students and staff is not sure.
All of these (can) have a social networking side, so you can share information and use them to collaboratively reflect on a shared experience. Also the use of tagging within each means you can separate comments on different subjects.