For viewing files, there are these options when you are within a folder:
Tiles gives you a view like this:
If you click on an individual photo, you can view them one by one, add to an album, share, order prints, etc. Hard to see all the options here:
Using "Photos" from that menu simply gives a larger tiled view of the photos.
The way I normally would sync a folder would be to drag it over to my OneDrive in Windows Explorer, then change the folder so it is available only online. (I made a mistake in a post earlier--the option is now called "Free up space" in the Explorer right-click menu, to make a file or folder online only.) But I can also drag a folder to the web interface and it will upload the folder and the files within it, with no other action needed on my part.
You can share individual files or entire folders. One "gotcha," though--make sure you untick the "allow edits" box when sharing. That is used more for collaborating on files when in an office environment, but if sharing for any other reason, there is no need for anyone else to be able to edit a file or folder in your account.
As for cloud hosting in general, it's misleading the way many of the marketing companies use the term "cloud." In essence, it is simply a virtual machine, or virtual storage space, within a large array of computers. You're not actually uploading to a specific server, but a cloud service which stores your data "all over" (I won't get into the technical end of it), as opposed to hosting it on one particular storage device, whether that be memory or a spinning hard disk. Redundancy is a benefit, as a failure of a single hard disk unit will not affect anyone's data.
It's
interfacing with the cloud that needs some work. OneDrive seems to have it fairly well implemented, as do a few others, and every so often I find little improvements. I know they all need to listen to their users more, however. Windows and OneDrive had removed the "offline only" support for at least a year, and only re-introduced it as the "Free up space" option just recently. I'd say the cloud services right now are varying degrees of "good" but not yet "excellent." Each one probably lacks a major feature or two we'd all want to have.