There came also sixteen of the order of Windrunners, and with them a considerable number of squires, ... 
Powers and AbilitiesEdit
A squire is able to hold Stormlight, although much less efficiently than a true Knight Radiant; it is unclear if they remain less effective than a Knight Radiant, or if, over time, they are able to become nearly as powerful as a Knight Radiant. This Stormlight ability likely grants them only the powers of the Knight Radiant they follow, but such speculation remains unsubstantiated at this time.
The Lopen sucked in Light ... . He felt at his shoulder, the one where he'd lost his arm so long ago. There, his fingers prodded a new nub of flesh that had begun sprouting from his scar.
Further, the effect occurs to multiple unnamed members of Bridge Four during the Battle of Narak.
|“||"At the end there, right before you arrived . . . Storms, son, I swear I saw a couple of the lads glowing. Faintly, with Stormlight."||”|
In the first place, Lopen mentions constant practice, earnestly willing himself to take in Stormlight; on the other hand, those fighting on the Shattered Plains seemed to spontaneously manifest their abilities. In both instances, it seems to grant them abilities similar to those of Kaladin: enhanced speed, strength, and healing. Neither of these, however, are recorded until after Kaladin has spoken the Third Ideal of the Windrunners, suggesting there may be a link to the strength and honor of their Knight Radiant.
|“||"I've been listening to readings of those visions Brightlord Dalinar sees, ... From what I can guess, it seems that the orders of the Knights Radiant were made up of more than just the Knights themselves."||”|
It is unknown at this time whether these squires have any other powers, or if they are able in the future to obtain further powers, perhaps even bonding with a spren of their own. It is unclear if the other orders of Knights Radiant follow this same pattern, although it seems likely. More will need to be revealed in order to fully understand the potential and process of becoming a squire.
Variation Between OrdersEdit
There seems to be a fair bit of variation between Squires of different orders. According to suggestions within the text, ...
Also, some orders were individualistic, while others - like the Windrunners - functioned in teams, with a specific hierarchy.
This is further supported as well by Q&A's with Brandon. Certain orders of Knights (like the Windrunners), tend to generate a great number of Squires, while other orders (the Bondsmiths, perhaps) generate very few. Also, the power available to Squires seems to vary according to the order to which they each subscribe; whether this means that some can access limited Surgebinding, that they utilize Stormlight more efficiently, or that they can grow in strength more rapidly than the Squires of other orders, is currently unknown.
Q. Do squires always bond the spren of their Knight’s order? Or can they attract a different type of spren?
A. They can attract a different spren.
Q. Also, was it normal for someone to serve their whole life as a squire?
A. It was indeed normal, depending on the order and the person.
Q. In the original Knights Radiant, when they had squires, were all of the squires destined for bonding spren?
A. No. Many stayed squires forever and that was okay.