For all those scoffing at the idea of Mac Apps being difficult to install now, let's just review the possible options:
1. Download the DMG, double-click to mount (if not auto-mounted). Drag app to Applications folder (sometimes via a provided alias, but usually not), then unmount Disk Image and delete DMG file. Ease of use: Good. Intuitiveness: Not so good (especially for users coming from Windows). I can't even count the number of times I've seen someone running Skype or Firefox from the disk image every time, and then they trash the dmg file at some point thinking it's just a useless extra, and suddenly their app doesn't work any more. It's not a bad method, but it doesn't make sense unless there's good instructions in the download (some developers do a good job here, many don't).
jW