Default service priority

[Martin Atkins]

Johannes Ernst wrote:
> If a service priority is not specified for a YADIS Service element,  but
> all other Service elements have it, how should those Service  elements
> be sorted? In other words, does the priority default to 0,  to
> Inifinity, to -Infinity, ...?
> 

I don't think it really makes much difference. Just pick one.

Another possibility is to copy HTTP negotiation which (I think?) uses 1
as the default and expects lesser items to be fractions of 1.

Might also be good to check to see if XRD already specifies this.

I think what's more important is to properly explain the meaning of
priority; namely, that it only comes into play when the relying party
really has no other means to decide on an item. And even then, some
relying parties will probably just take the first one encountered and
use it no matter what the spec says, because people tend to take
shortcuts like that.

In other words, if you specify both LID and OpenID auth and prioritise
OpenID, some relying parties might use LID anyway because they have a
superior LID implementation, they don't support OpenID at all, or if
they just like LID more, or whatever.