Specific personal jurisdiction issue

The CAFC noted in Campbell Pet Co. v. Miale:

As the district court noted, even where general jurisdiction is not available,
specific jurisdiction may be exercised by a district court in the forum state if the state’s
long-arm statute would permit service of process on the defendant under the
circumstances of the case, and if due process considerations would permit the exercise
of personal jurisdiction over the defendant under those circumstances. See Omni
Capital Int’l Ltd. v. Rudolf Wolff & Co., 484 U.S. 97, 104-05 (1987); Burger King Corp. v.
Rudzewicz, 471 U.S. 462, 471-76 (1985). In a case such as this one, in which the
state’s long-arm statute extends to the limits of due process, the two-part inquiry
collapses into one—whether due process considerations permit the exercise of
jurisdiction. Resolving that question requires the court to address two issues that bear on
whether the defendant has purposefully established minimum contacts with the forum
state: (1) whether the defendant “has purposefully directed his activities at residents of
the forum”; and (2) whether “the litigation results from alleged injuries that arise out of or
relate to those activities.” Burger King, 471 U.S. at 472-73 (citations and internal
quotations omitted). If the court concludes that those two conditions are satisfied, a
third factor comes into play, i.e., “whether the assertion of personal jurisdiction would
comport with fair play and substantial justice.” Id. at 476, quoting Int’l Shoe Co. v.
Washington, 326 U.S. 310, 320 (1945).

The CAFC got into the matter of a patentee sending a warning letter:

Based on that rationale, we have held that “the sending of an infringement letter,
without more, is insufficient to satisfy the requirements of due process when exercising
jurisdiction over an out-of-state patentee.” Inamed Corp. v. Kuzmak, 249 F.3d 1356,
1360-61 (Fed. Cir. 2001) (citing cases).

The CAFC got into the specifics of what went on IN THIS CASE at a trade show:

In this case, the district court erred by characterizing Ms. Miale’s actions at the
June 2007 convention as constituting nothing more than attempts to inform Campbell of
suspected infringement. As Campbell points out, its employees’ affidavits assert that
Ms. Miale did more at the trade show than simply inform Campbell that its animal
stretchers might infringe her patents. The affidavits state that Ms. Miale attempted to
have Campbell’s allegedly infringing products removed from the convention and that
she told Campbell’s customers that Campbell’s products were infringing. Of critical
importance to the issue of personal jurisdiction, Ms. Miale’s attempts at “extra-judicial
patent enforcement” were targeted at Campbell’s business activities in Washington and
can fairly be characterized as attempts to limit competition from Campbell at the Seattle
convention. Those efforts go beyond simply informing the accused infringer of the
patentee’s allegations of infringement.