It is true that a contractor generally retains ownership in any original work of authorship but AOL, in paying for the work, would get an implied license to publish that work as intended by the contract - that is its point in paying for it (much as any website owner who might fail to secure copyrights from a contractor who does work for his site, though he may not own the rights or be able to prevent the contractor from re-using the work elsewhere, nonetheless may use it for his own site in having paid for the work for that purpose). Thus, A DMCA takedown notice could not be used to remove any of the articles.

Contracts of this type also would normally be expressly framed as work-for-hire contracts and would also provide for the assignment of all rights to work that did not technically meet the criteria of works made for hire. Such clauses are valid and enforceable and are indeed a staple of every tech developers invention-assignment agreement. They apply with equal force to works of authorship by an independent writer. Assuming the contract here is so framed, AOL would own the copyrights in the works of the author.

The employee-contractor question, on the other hand, is a tricky one. This is a murky area but one where, generally, the lower the skill level and the more the worker must abide by company-defined procedures and schedule in how the work is done (among many other factors), the greater the risk of being classified as an employee. Many writers work independently with no risk to anyone of their being treated as employees but the AOL situation described in this piece might be vulnerable to audit risks owing to its assembly-line aspects. Hard to say without knowing a lot more detail.