For me, Flickr is more of a dumping ground for my images. For what I consider to be my best images, I share those on 500px. You already have a web address you can tell people. It's flickr.com/photos/yourusername. If you want something more personal, you'd have to register for a domain and have it redirect to flickr.com/photos/yourusername.
For information purposes, my pan is the result of stitching four landscape photos, if that makes any difference.
One tip for the next time you plan on shooting a panorama, shoot the individual images in portrait orientation. You'll need more images to cover from left to right but you wind up with more detail top to bottom.
I'm shooting products for a friend and they need to be a minimum of 72dpi and 500px.
If they need to be a minimum of 500px, they can be larger than 500. Depending on the end result, I would export at the largest resolution possible, without upsizing.
The latest version is 6.4. When you do "File-->Open Catalog", you're only opening the catalog which references images. Most people have one catalog for all their images. My guess is you imported the images into a different catalog than you think they're in.
I store all of my images on one external drive. I sync the images to a second external drive. I also have TimeMachine running constantly, as well as backing up to CrashPlan. When I import into Lightroom, my Dropbox app also copies the images to a folder which gets synced to the Dropbox servers and to my other computers. At any one time, I have at least four copies of my images, on 3 drives and 2 online services.
I'm not seeing it selling anywhere for less than $142.
You have to buy from Adobe. http://www.adobe.com/products/photoshop-lightroom.html
Go to the very bottom. Click "Buy Now" under Lightroom 6. Choose the $149 option. When you get to the cart, change from Full to Upgrade, and which version upgrading from. You should see $79 reflected in the cart.