The internet is not for wholesale copying of other people's work onto your own site, no. Are you going to get a DMCA takedown from AdWeek? Highly unlikely, though they'd be within their rights to do it. But it's still a crappy practice. And I take it personally because I work for a publication, and people do it to us all the time, and it's incredibly rude.
The proper way is to excerpt a small portion and link to the full article if anyone wants to read the rest.
Why would anyone bother visiting the article if they can already read the whole thing on your site?
It's all well and good to credit the author, but he doesn't get the page views, and the site doesn't get the ad revenue.