What is the best way to determine if my web application is eligible for a patent and/or copyright?
I don't know where to start for someone to review my SaaS business to understand what I can patent and/or copyright. Where should I start with learning about whether I can get IP protection for my app?
You're already covered by US copyright the moment you create any content, text, graphic designs, etc. for your site. It's not required, but it's still a good idea to put a copyright notification on each item you wish to protect (like this: "Copyright 2015 NameOfCopyrightHolder"). Protection now lasts for about 70 years, if I recall correctly, before renewal is required. You need not register your copyright with the Library of Congress, but this is also a good idea. Do it yourself for under $100. Visit www.copyright.gov for more.
For the stuff "under the hood" of your app you will need a patent, which is not in my area of expertise at all. You'll probably also want to protect your app's name with a registered trademark. Both patents and trademarks are handled by the US Patent Office. See www.uspto.gov.
I've found LegalZoom to be a good source of legal advice, and I know they have affiliated attorneys who are knowledgeable about these issues. The cost is very reasonable to pick an attorney's brain for a half hour or so.
I hope this is useful to you.
In EU the IPP agency provide the optional evaluation service, not sure if similar is available in the US. Alternatively a professional expert of copyright can maybe help you: follow just an example for you to start your own investigation/research http://www.theexpertinstitute.com
To learn about a US copyright, check out this US Copyright Office informational page: http://copyright.gov/circs/circ61.pdf.
There is no shortage of patent attorneys in the San Francisco area. I'd suggest calling someone like Repetto Law (small office) and ask if they provide free consultations to get the information you need.