and again, what does the assessment mean to me?
Per the Allentown Morning Call, here is what Lehigh County in NE Pennsylvania is sending out right now... and remember, Lehigh County started their assessment process years after Allegheny County started... so it isn't the case Allegheny County has not had time to do something similar. Anyway, per the MC:
The assessment letter should tell you that your taxes are projected to increase or decrease. For estimates based on current tax rates, you should go to mylehighcountyproperty.com and enter the control ID listed in the upper right corner of the letter. You can also call the assessment office and provide your control ID. While they won't tell you over the phone, they will mail a tax estimate to you.
and so.. if you want Allegheny county do do the same for you, maybe you want to contact your county council representative. It would be a fairly simple thing for the county to do here. No reason they still can't do it.
For the City of Pittsburgh my colleagues made the map below showing the valuation changes per parcel for the city of Pittsburgh. You can get a high resolution version of that via this post or access an interactive map to zoom in ever further via this post. Note the map is not showing tax changes, but just the changes in property values. No adjustment is made for the millage changes which will be mandatory.