Did you know that Hymnary.org allows you to compare a number of instances of the same text side by side?
For example, if you go to the text authority page for the hymn "Come, Thou Fount of Every Blessing" you'll find 19 instances (unique appearances in particular hymnals) of the text. Of these, 15 include full text in their Hymnary.org record. Above the list of instances, you'll notice something that says "Instances of this text - compare...<" Click on the word "compare" and a column of checkboxes appear. Here's where it gets fun: check any boxes of hymn versions you'd like to compare, then click "compare selected" below. Voila! Now you have different versions of the text lined up side by side for comparison. You can even change the number of columns and text size.
And what interesting things do we find? The widest textual variation centers on the phrase "Here I raise my/mine Ebenezer." Some editors must have found this biblical reference too obscure, so the Epsicopalians and CRC changed it to "Here I find my greatest treasure," Worship & Rejoice uses "Here I raise to thee an altar" (not a bad choice, since the Ebenezer was an altar or monument of sorts), and the Celebration Hymnal chooses "Hitherto Thy love has blest me, Thou hast bro't me to this place." (I'm not sure what is gained by replacing the obscure "Ebenezer" with the antiquated "Hitherto," but there you have it...)
If we wanted to have even more fun, we could go back to the text authority page and click on "Include 1670 pre-1979 instances" which would give us 1,689 instances, including the hymn's appearance in Southern Harmony. Or we could read an overview of the hymn in the Psalter Hymnal Handbook, or find a biography of the author Robert Robinson in Julian's Dictionary of Hymnology, or...
As you can see, at Hymnary.org, the fun just doesn't stop!