diff --git a/content/blog/v7-13-formulas-and-regex/index.md b/content/blog/v7-13-formulas-and-regex/index.md
index 50f206c..403a921 100644
--- a/content/blog/v7-13-formulas-and-regex/index.md
+++ b/content/blog/v7-13-formulas-and-regex/index.md
@@ -170,3 +170,27 @@ The shipped demo data includes the regex rules on `MPE_X_TEST`, so you can see t
 For formulas, add a rule to one of your own tables - the `REVENUE = PRICE * VOLUME` example above is a two-minute configuration, and the `DC.*` special values make audit-style columns almost free. Full reference in the [validations docs](https://docs.datacontroller.io/dcc-validations/).
 
 As ever - if you'd like to see additional validation types, [get in touch](https://datacontroller.io/pricing). The roadmap is customer-driven, and the validations list keeps growing.
+
+<!-- Source LinkedIn post:
+
+Your reporting tables keep needing derived columns - and until now, the answer was a SAS hook script.
+
+Change a price, and the revenue column updates itself. Stamp the user who made the change, in the same row, automatically. And when an email address doesn't look like an email address - block it before it ever reaches production.
+
+Data Controller v7.13 ships live formulas in the editor grid. Configure a column with a rule like = PRICE * VOLUME and the value is computed on entry, spreadsheet-style, using the full function library (IF, SUM, ROUND and friends). A HARDFORMULA locks the column; a SOFTFORMULA lets the user override when the business needs it.
+
+It completes the story started in 7.12 with regex validation - HARDREGEX blocks invalid patterns outright, SOFTREGEX highlights them as a warning. Both are one row of config in MPE_VALIDATIONS. No code, no deployment.
+
+There are also special runtime values - so an audit column can read "sasdemo changed from orig-2" without anyone typing it:
+
+=IF( DC.ROW_STATUS ="U","unedited",
+  DC.USER_NAME &" changed from "& DC.ORIG_VALUE )
+
+Full write-up with live screenshots (and how the rules flow from config table to grid):
+
+Link in the comments 👇
+
+#sas #datavalidation #dataquality #endusercomputing #datacontroller
+
+First comment: https://datacontroller.io/v7-13-formulas-and-regex/
+-->