I mentioned that this wasn't a solution for the multi-photographer studio but it could be useful if your images are housed on an external drive and you like to work from multiple computers. The cloud based catalog has the advantage that all of the changes you make reside there and are accessible to your various computers. If you are using a free Dropbox account (you get 2GB free when you sign up!) you will run out of room quickly as your previews file grows. The .lrdata file gets big if you use 1:1 previews and like to keep them.
Since I wrote that article, Dropbox has added a feature called Selective Sync. A Lightroom Secrets reader, David Balder, sent me an email pointing out that this new feature removes the preview bloat issue and can give you more room to store your catalog. Thanks, David! That's a brilliant suggestion!
David suggests that you use Selective Sync to exclude the .lrdata file from the Dropbox sync. The downside here is that you will lose your previews. However, Lightroom will happily build them as needed when you start to work in your catalog. So there's the tradeoff: a little more time to build a preview in exchange for more room in your free account to store a catalog.
Here is how to implement David's suggestion. Start by clicking the Dropbox icon in your menu bar to access Preferences…
In the preferences dialog go to the Advanced tab and choose Change Settings for Selective Sync.
If you aren't already there, choose Switch to Advance View at the bottom of the resulting dialog.
Once you are in Advanced View you can navigate to your .lrdata folder and uncheck the box.
This will remove it from your Dropbox sync going forward. Press the update button and you will be reminded of that.
Press update again and you're all set.
Thanks again, David!