Professor Webb here is a strange beast. He's a lesser version of Scavenging and a different version of In the Know rolled into one ally. I say lesser version, because Scavenging proper doesn't use secrets and will net you a clue as well. And In the Know can target any location, not only connecting ones.
Webb has a benefit, however. His ability is a to a successful investigation at your location, so you can decide if you want to use his ability after you've succeeded at the test. So, you'll never waste a secret, and you can investigate at locations with no clues and still trigger his ability.
So, what can Webb be used for?
1a) Webb can serve as a Scavenging for those without access to assets. Now, Webb only has three Secrets to burn, so he's less useful than the limitless Scavenging. Scavenging does have the if succeed by two clause but will get you both a clue AND the item. But while Webb is inferior, he will return three items to your hand and if those items are juicy enough (The Necronomicon, Grotesque Statue Key of Ys) he might be worth your time.
1b) Any investigator whose deck is built around Scavenging can use Webb as a extra copy. But anyone with access to Scavenging also has access to Short Supply and Resourceful so a backup might not be needed.
2) Webb can pick up clues from connecting locations rather than the one you just investigated. This can be useful, but it's quite conditional. You need to have a revealed location next to you, with a clue that you want to pick up. And with only three Secrets to Webb's name, it's not like you can use this ability willy-nilly.
3) Webb can be a swiss knife ally for an investigator who both benefit from the Scavenging ability and the ability to find clues at connection locations.
Let's look at candidates for the different user cases:
1) Scavenging Webb: Anyone who plans to recycle high value items such as The Necronomicon and Key of Ys can certainly use Webb. Right now that archtype belongs to seekers with access to Survivor cards (aka Minh Thi Phan), but you might want to try a Harvey Walters+The Necronomicon-build with Magnifying Glass glass to discard emtpy tomes and then get them back up again with Webb. The problem here is that seekers already have lots of ways to play with tomes, so Webb seems like a detour. But it's still my favorite combo.
2) In the Know-Webb: Webb can help shore up up the "seeking from afar" archtype along with Pocket Telescope and In the Know. You'll need some way to generate secrets, but it's doable. The prime candidate is Luke Robinson, who can use Webb to investigate from the safety of his 1 Shroud Dream-Gate.
3) Swiss-knife-Webb: Again, late game Luke with some sort of intellect buff and Grotesque Statues, and probably Charisma, Whitton Greene and a way to replace lost secrets that might go to Webb if needed.
Professor Webb has a level 2 version as well. The difference is +1 Sanity, a pip and that you'll always activate both his abilities. so he's a Scavenging without the succeed by 2 clause that can find clues either on your location or a connecting location. It's neat but in my humble opinion, triggering both isn't worth 2 xp.
Seekers and survivors both have great awesome allies that's awesome by themselves. Webb is not one of them. He has no stat buffs and he needs to be part of some sort of combo. I have listed a few combos above but ally slots are valuable, and Professor Webb seems mediocre at best.
What do you think? Is Webb worth it because he has two abilities and thus easy to get milage out of? Or is he simply not good enough at what he does?