Running a membership website can be fun and profitable, and it's not that hard to start running one. However, you should consider some things before running one.
The first is that you will need to come up with content on a regular basis. Your site works best when members return to the site, and they will return only when they have a reason to return. The most effective draw is new content and you need to find a way to do that. Written content is the most obvious, and easiest, but podcast, video, and other graphic content should also be considered. Ideally, you should update at least three times a week, but as long as the content is worth the wait, your members should continue coming back.
If you don't have time to create new content, you may need to consider hiring someone to create the content for you. There are number of freelancing sites that you can explore. You just have to know exactly what you need done so that the freelancer can do his job effectively. Of course, if you are using more than mere text, you can get whomever you want to create content, but keep in mind that written content is the cheapest and easiest way to create regular content, and those details make it optimal for your purposes.
You also need to keep advertising your site. There a re number of ways to draw new members in, and you should try as many as you can think of and reasonably afford. The advertising can be being either free or reasonable, but you need to determine what the most effective method for you will be. Keep in mind that there are a number of free means of advertising out there, but they will require time on your part in order to work; there is no such thing as a free lunch, and the cheaper the lunch, the more work you need to put into it to make it work.
Don't forget the site maintenance issues. You need to check out comments, making sure that they are acceptable and that you aren't being spammed. You need to listen to your members, and make sure that all of your links work. You also need to shift some content around; especially if part of your draw is that, your content may be deleted at regular intervals. Of course, make sure that you back the site up, in case something happens to the content.
As part of your maintenance, you need to check your numbers and see what links and keywords are drawing people to your site. It can be interesting to see what keywords are driving people to your site, especially when the best working keywords aren't expected. In addition, don't forget to venture off-site! You need to make sure that links to your site work, as well links from your site. Site maintenance can be a lot more work than just processing membership requests.
Running a membership site can be an interesting project, but it requires a certain amount of work in order to ensure that it's running well. Like any other business venture, the effort that you put into it will return to you. The more effort you put into it will be returned, with interest. Remember that and you membership site should do well!