Most of this Gigalaw how-to article on linking and framing isn’t objectionable, but the best practice suggestion, “Don’t Deep Link Without Permission,” seems like overkill. There is no caselaw to suggest that deep linking is per se illegal. The two cases cited involved more than linking, but presumably misappropriation of data.
Disclaimer: Not being your lawyer (as far as I know), I’m not rendering advice I intend for you to rely upon. I’m just saying some of the other advice on the Internet perhaps shouldn’t be relied upon.