Websites that specialize on a topic and that publish with regular columnists and at regular intervals can be found here.
A longstanding source of great information, Digital Web Magazine is an online magazine intended for professional web designers, web developers and information architects
.
The excellent content is all free, and there is mountains of information from many different categories available.
From their about page:
Boxes and Arrows is the definitive source for the complex task of bringing architecture and design to the digital landscape.
Treehouse magazine, published by the knowledgeable folks from Particletree, is a PDF magazine dedicated to web development. It's quite an attractive piece of work, and aims at containing resources, tutorials, links and much more.
A subscription based online PHP mag that aims to be the monthly magazine dedicated exclusively to professionals who use PHP as part of their everyday work
.
They offer a free issue for download and generally have one free article available per month, and the site has some busy forums and webcasts available.
Vitamin is a resource for web developers, designers and entrepreneurs
publishe by the tireless folks behind Carson Systems.
It's a bit light on content compared to the other publications in this category, but in time it will surely become a superb web development resource.