Every website, company or group can let its users get together without having to plan anything.
People want to meet and if you give them the right tools to do it, they will be thankful. If that tool also helps you market your ideas and products to them, then it's good for all involved.
Vote with the crowd on a place to go tonight
Freshers, startups, expats, Flickr photographers, undergrads, flatmate seekers, new in town, cyclists... and many more
Step 1: Choose your crowd
Step 3: Feel welcome with a great crowd in a place you all chose
If you owned the service which brought them together, you could also direct the conversation and so this becomes a new marketing channel.
Create your own crowd group
It takes 60 seconds to create your own group here: http://www.likeourselves.com/?lid=create
Create tags within that group
For example, if the group is 'Flatmate seekers' the tags might be 'non-smoker', 'West' and 'budget 600-800'
You create that group with tags and it shows up to users like this:
They select the tags and when they've voted on a place to go tonight, they can see which of their tags match to every other user going there:
By owning the group, you will own a unique growing network where offline conversations can be directed to your service via tags, which themselves are adverts users feel motivated to select.
This in turn increases page views, user numbers and consequently, revenue. In addition, you will own a channel covering a geographic area that, once established with large numbers, is very difficult for competitors to replicate.
Have a look at the user home page http://www.likeourselves.com, sign up and play with it. Then go to the groups and tags page to create your own group.