Chrome: No one has time to click on every link they see online. If you'd like to get a preview of a page just by hovering over the link, Streamfully is a new extension that will show it to you.
It's similar to previously mentioned CoolPreviews and SwiftPreview, with a few key differences. Most importantly, it's more personalised. Instead of previewing the entire page, Streamfully shows you snippets of the page based on your reading history:
If this is a new topic for you, Streamfully shows you the page's important content starting from the top. If you have touched this topic elsewhere, Streamfully shows you something new but connected to what you've been interested in before -- just like a conversation. Streamfully is a new generation of discovery engine because it creates a "conversation with content" that personalizes down to the snippet.
It will also pull in related content from elsewhere on the site you're on or around the web, again, depending on how well Streamfully knows you.
On the other hand, if you just want to preview links, you're probably better off with one of the other extensions, since Streamfully isn't as customisable or robust in that regard (there's no Shift hotkey, for example, to limit the link previewing, though you can easily turn Streamfully on or off by clicking its icon in Chrome).
Otherwise, if you're looking for something that both summarises links and connects different pages you might be interested in, give Streamfully a try.