Of the three services tested, Glip offered the most granular control over notifications that it sends via email or by text to your mobile phone. (Flow comes with some customization but not as much.) For example, it can play a sound when a new message arrives or send just an email notice.
Glip supports groups of users in two different ways: You can set up teams for particular projects or create ad hoc groups of three or more users to share some documents quickly.
Glip is also the most extensible of the three services. Its integrations are fairly effortless, including the ability to share files from your accounts on Google Docs and Dropbox and to synchronize events to your Google Calendar. You merely follow the pull-down menu choices; there is no need for any additional action outside the workflow.
There is also a list of upcoming integrations; users can vote on their priorities, a nice crowdsourcing touch. However, you can't do any collaborative editing in the conversation stream; you have to leave Glip and use another service such as Google Docs or Dropbox.
There are also extensive FAQs and help screens, but the user interface is very clean and I didn't need much support at all to get up and running.
Glip comes in Web, iOS and Android versions; the mobile apps retain most of the look, feel and functionality of the Web app.
The service has a generous pricing schedule: It is free until your workgroup hits 10,000 total posts, 5GB in storage or 500 video chat minutes. After that, it costs $5/user/month or $50/user/year. Once you pay for your account, you become the admin for your domain, which is so incredibly simple that I wonder why other services haven't done something similar.
Glip has the most features and is the easiest to use of the three services I tested. Its mobile clients also come very close to matching the features and user interface of the Web experience.
Slingshot is the only service of these three that offers both screen sharing and lightweight video/audio conferencing. You wouldn't use this tool for running a large meeting with dozens of participants, but for more limited (up to about 10 people) collaborations it works well.
During a Slingshot audio/video session, you can also create text chats and meeting notes, just like WebEx and other conferencing tools.Click to view larger image.
You set up a video session and then each participant connects using a local Slingshot client, either from a mobile device or from a desktop app. Both apps have a small series of menus in a narrow column, very like services such as GoToMeeting. But Slingshot lets you share anything that you have on your mobile device, while GoToMeeting allows you to share only Web pages and Office documents.
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