Firstly this is really just an extension of an inherent problem with links in the first place, which is that the target doesn't need to have anything to do with the link text - even if the link text looks perfectly adequate. In fact I would suggest that a well written text link is even more likely to engage and fool the user than a shortened link which might actually make you stop and think 'what is this' before clicking it.
Some users care about shortened URLS - and some don't. I don't have numbers to hand, but the important thing is that more and more users are either becoming aware or being made aware of the issues.
Take this blog article from MailChimp for example which gives advice to their users and even provides a tool for unfurling links. They even take care to use a font which helps highlight issues.
Advanced users or not, we should care and we should eliminate the issue so that users don't need to care.
Bitly and others provides tools and plugins for being able to hover over a link to find out information, but still this is aimed at advanced users. They do highlight the problems of abuse in their help and FAQ's, and those providers that highlight the issue more, and are proactive about removing problematic urls, are likely to be more trusted.
On mobile, where hover is not possible, it's impossible to see where a link goes and with mobile device usage exploding (and desktop usage slowing) it's only going to become more of an issue. I would maybe like to see an intermediate popup for URLS that do not match target and text, that shows the target URL in full detail and confirming whether you want to go to that page, but with the extent of chaining that spammers can use to abuse the system, I doubt there's much that can be done. You could even auto-detect the relevance of the target to the link, content, and immediately surrounding text in order to determine the risk - that would be cool!
We should all be educating users as much as possible as to the existence of the problem; the tools and plugins available to help them; and advising them to avoid clicking unknown links from untrusted or unknown sources in email, search engines, and social media sites, especially new content.
At the end of the day it's a question of:
- do you trust the publisher
- do you trust the source
- do you trust the content
- do you trust the link